Electric furnace.



' No. 722,411. PATENTED MAR. 10, 1903.

A. A. SHADE.

ELECTRIC EURNAGE.

Y APPLICATION FILED MAY 15. 1902.

2 SHEETS-SHEET 1.

'I0 MODEL.

IHIIHIHHIIIIIHHHI n n f i i u n No. 722,411. PATENTBD MAR. l0, 1903.

' A. A. SHADE.

ELECTRIC FURNAGE. APPLICATION FILED MAY 15. y19m. l No Monia.. 2 SHEETS- SHEET 2.

of n y D 4 I ,H E y UNITED STATES PATENT OEEICE.

ALBERT A. SHADE, OE CHICAGO, ILLINOIS,'ASSIGNOR OF ONE-HALE TO EUGENE HOWARD MOORE, OF CHICAGO, ILLINOIS.

ELECTRIC FU RNACE.

SPECIFICATION forming part of Letters Patent No. 722,411, dated March 10, 1903.

Application led May 15,1902. Serial No. 107,435. (No model.) I

T0 @ZZ whom, it may concern:

Be it known that I, ALBERTA. SHADE, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Furnaces; and I do hereby declare that the following is a full, clear, and eXact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in electrical furnaces for smelting or reducing ores and other similar substances; and the invention consists in the matters hereinafter set forth, and more particularly pointed out in the appended claims.

In the drawings, Figure l is a vertical longitudinal section of an electrical furnace made in accordance with my invention. Fig. 2 is a transverse section taken on line 2 2 of Fig. l. Fig. 3'is a transverse vertical section taken ou line 3 3 of Fig. l. Fig. 4 is a longitudinal horizontal section taken on line 4 4 of Fig. l. Fig. 5 is a detail section taken on line 5 5 of Fig. 3.

The furnace herein shown in which my improvements are embodied is providedwith a chamber or passage through which the material to be reduced is passed, said chamber having a refractory wall made of fire-brick or like material. Said passage is inclined downwardly from the receiving to its discharge end and provided at its upper end with means for feeding the granular material to the furnace and at its discharge end with means for withdrawing the molten material from the furnace. Extending into said passage are a plurality of electrodes arranged in opposing pairs, between which the material passes, said electrodes being arranged to form arcs, by which the material passing between t-he electrodes is heated and fused, and said arcs are deflected or elongated toward the passing material, so as to localize or intensify the effect of the arcs on said material.

As shown in said drawings, the body A of the furnace consists of fire-brick or like refractory material, as shown in Fig. l, and said furnace is provided with an elongated inclined passage A', through which the material to be fused is passed by gravity. The upper end of the passage is the receiving end and the lower end thedischarge end, from which the fused material is withdrawn from the furnace. Said furnace-body is preferably surrounded by a metallic shield A2, consisting of metal plates suitably secured together, and the spaces between said shield and the tire-brick body of the furnace is filled with a body of insulating material A3, such as mineral wool, asbestos, or the like.

The bottom of the passage A is transversely curved, so as Ato form an elongated troughlike receptacle Ct, through which the material passes. The upper side of said passage is arched, as indicated at a, and made of suitable dimensions to provide space for the gases generated by the fusing material. The troughlike depression of the passage is shown as provided with a lining of suitable refractory material.

Extending through openings in the side walls of the furnace and into said passage A are a plurality of 4carbon electrodes B B B B' B2 B2, the electrodes being arranged in opposing pairs and those of each pair inaXial alinement, as shown in Fig. 4. Said electrodes are located above the trough-like bottom of the passage VA, and the series are shown as located closer to the lower end of the passage than the upper end thereof, the

last pair of electrodes of the series being closely adjacent to the discharge end of the passage. Located centrally between each pair of electrodesand supported in any suitable manner in the wall of the furnace are a plurality of magnets C C C2, which act upon the arcs formed between opposing electrodes to elongate or deflect said arcs into the trough a of the passage A/, whereby the heat of said arcs is intensified and localized upon the material as it passes through the arcs. When making the furnace, the wall thereof is provided with a plurality of recesses opening at one side of the furnace to receive said magnets, and when the magnets are inserted in place said openings are desirably closed by permanent masonry. The tops of said openings or recesses are arched, so as to permit lo@ ing the general masonry construction of the Walls. Said magnets are herein shown as electromagnets; but it will be understood that horseshoe-magnets may and will desirably in practice be employed and that I may use either electromagnets or permanent magnets. I prefer, however, to employ electromagnets, for the reason that I am enabled thereby to vary the strength of the magnetic currents, and therefore more accurately adjust the same to the strength of the electrical current used to produce the arcs between said electrodes. The wiring by which said magnets are connected is not herein shown; but it is to be understood that the usual or any desired practice may be followedl yin this respect.

In order to localize to an extent the fields of force of the magnets, so that each magnet will act effectively upon the arc of its associated electrodes, metallic shield-plates E2 E3 are employed, which are embedded into the wall of the furnace between the magnets. Said shield-plates prevent the lines of force of the magnet adjacent to the same from influencing the arc of the electrodes not associated therewith, so that all of the force of each magnet is utilized to draw or elongate its arc downwardly into the trough-like depression of the passage A.

The trough ct of the passage A terminates in a spout A4 of suitable refractory material, which is adapted to deliver the materialinto a'crucible or other vessel (not shown) located to receive the same. Said terminal end of the passage may, however, be otherwise constructed, as best practice may dictate. The lower end of the passage A is closed by a door A5, which may be hinged to the wall of the furnace to swing outwardly away therefrom, and said door is provided on its inner surface with a lining A6 of fire-brick or like refractory material. This door aords access to theinterior of the passage of the furnace for the purpose of cleaning the same and for other purposes when such entrance is desired. The top inclined wall of the furnace is provided with a number of peep-openings a2 a2, arranged to permit observation of the operation of the furnace. Extending across said peep-openings are plates of transparent substance a3, such as mica, which are held between outwardly-facing shoulders in said walls and the movable retaining-rings a4 of suitable refractory material. The outer ends of the openings are closed by doors a5 to protect the mica a3. These openings are arranged in alinement with or opposite to the arcs, so that an operator may be enabled to determine the action of each arc upon the material being operated upon.

The material is delivered to the upper end of the passage throughthe medium of a pipe D, which communicates atits lower end with said upper end of the passage and at its upper end with a conveyer-shell E. Said pipe D is desirably made of a suitable refractory material. Said conveyer-casing communicates at its other end with a pipe F, communicating with a hopper F', through which the material is delivered to said several passages. The material is conveyed through the shell E by a screw conveyer E, as shown in Fig. l, the shaft e of which has bearing in the end Walls of a chamber G, surrounding the shell, and said shaft is provided with a pulley e', by which the conveyer may be operated from any suitable source of power. The feed of the material to the furnace-chamber may be regulated by varying the speed of the conveyor.

Preferably the gases from the chamber or passage A of the furnace are discharged from the furnace through the casing G above referred to and which surrounds the conveyer-shell E, whereby the heat of said gases may be utilized for the purpose of preliminarily heating or drying the material before it is delivered to the passage A. For this purpose the chamber G communicates with the passage Al of the furnace through a pipe G', made of suitable refractory material, and said chamber G is provided with a plurality of radial partitions g g g2,- extending from end to end of the casing and from the wall of the casing to the conveyer-shell, said partitions thus dividing said chamber G into three compartments g8 g4 g5. The partition g is provided at the outer end of the casing with an opening g, as shown in Fig. l, which affords communication between the chambers g3 g4, while the partition g2 at the opposite end of the chamber G is provided with a like opening Q7, which opens communication between the chambers g4 and g5. The gases from the furnace pass first into the chamber g3, thence through the opening 96 into the chamber g4, and thence through the opening g7 into the chamber g5, from whence it passes outwardly through an annular opening gS between the hopper F and a conical casing G2, surrounding the same. The gases thus traverse the length of the chamber G three times before passing out into the open air.

I have also shown means for further preliminarily heating the material before it reaches the arcs, which additional preliminary heating means are made as follows: II H' I-I2 designate gas-pipes which enter th rough the opposite walls of the furnace and open into the passage A thereof in three opposing pairs, said pipes being located between the first pair of electrodes B and the receiving end of the furnace. Said pipes open into the passage just above the level of the troughlike depression a thereof, as shown in Fig. l, and are directed downwardly to throw the burning mixture carried thereby against the material passing through the furnace. Said pipes are supplied with gas through the medium of supply-pipes H3, one at each side of the furnace, and the pipes H to H2, inclusive, are connected with the supply-pipe through the medium of mixers, consisting of flaring- IOO IID

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shaped casings 7L 71' h2 on the pipes H H H2 and nozzle-pipes 7127# h5, communicating with the supply-pipe H3 and discharging into said flaring ends of the pipes H H H2. Said nozzie-pipes h to h2, inclusive, are provided with valves for regulating the passage of gas therethrough.

The openings in the furnace-wall through which the electrodes B to B2 extend are provided with refractory linings a6, as clearly shown in Fig. 3. Said electrodes have interlocking connections at their ends, thereby providing means for continuously feeding the electrodes to the interior passage of the furnace as the inner ends of the electrodes are consumed. As herein shown, each section of the electrodes is provided at one end with a dovetail-shaped lug b, which is adapted to enter a complementary socket in the end of an adjacent section. Said socket extends laterally across the end of the sections, whereby the electrode-sections may be joined by forcing said lugs laterally through said sockets. In placing the electrodes in the furnace the socketed ends of the electrodes iirstenterthe passages in the walls for receiving the electrodes, and said sockets and lugs are arranged horizontally,so that the upper and lower-jaws of the socketed ends of the electrodes act to hold lugs b of the adjacent electrodes in place until all of said connected parts have been burned away.

As a vmeans for feeding the electrodes into the furnace as the inner ends thereof are consumed and withdrawing the same therefrom in the operation of the furnace, I have herein shown said electrodes as provided on one side with spirally-arranged grooves and elevations, forming partial screwthreads b2, which are adapted to be engaged by the screwthreaded sections I of rotative shafts I', which are rotatively mounted in bearings I2, secured to the furnace-wall. Said shafts I are provided with hand-wheels fi, by which the shafts may be rotated to Withdraw the electrodes from the furnace or thrust the same thereinto. Each bearing I is provided with marginal flanges t', which engage guidebars I3, secured to the wall of the furnace, whereby said bracket may be raised to permit an electrode to be connected with an electrode in advance of the same. Said bearings I are adjustably secured to the guide-bars by means ot' set-screws i2, which extend through the bars and impinge upon the anges of the bearings. It will be understood, of course, that said electrodes are connected together before the outer end of the advance electrodes have passed into the furnace-wall.

The Walls of the furnace are provided beneath the electrodes with brackets J, having upwardly-facing concave bearing-faces on which the electrodes rest, and in order to prevent the electrodes rotating on their axes, and thereby disconnecting the threads thereof from those on the shafts, said electrodes are shown as provided in their under surfaces with longitudinal grooves 3, which are engaged by ribs j, located centrally of the concave bearing-faces of the brackets, as more clearly shown in Fig. 5. The wiring by which the several electrodes are connected is not shown; but it will be understood that the usual practice may be followed. It will also be observed that the several electrode-feeding devices are properly insulated from each other and the electrodes.

The operation of the furnace is as follows: In first starting the furnace in operation the electric current is turned onto the electrodes and the arcs produced between the same and the magnet-circuit is closed, so as to energize said magnets, and thereby deflect the arcs into the trough-like bottom of the passage A. The heat generated by the arcs acts to ignite the gas entering the furnace through the pipes H to H2, inclusive. The material to be fused is fed into the hopper F and is conveyed by the spiral conveyer E to the delivery-pipe D and while passing through the conveyer-shell is subjected to the heat of the exhaust furnace-gases and to an extent heated and dried. The material is dropped from the pipe D upon the trough-like depression a of the inner passage, at the upper end thereof, and descends by gravity from `the upper to the lower end of said passage. As said material is brought successively opposite the gas-pipes H to H2, inclusive, said material is impinged upon by the flames from said pipes and is further heated. Said material after being subjected to the two stages of preliminary heating in the manner stated is thoroughly dried and raised in temperature, whereby the fusing of the material by the arcs is promoted. The inner ends of the gaspipes will be suitably arranged to protect the same from the intense heat of the furnace. The material thus heated and dried passes successively between the arcs formed by the electrodes B to B2, inclusive, and the magnets act to draw downwardly or deflect the arcs so as to impinge the same upon said material, whereby the force of the arcs is localized or intensified upon the material to fuse the same. The material as it passes successively through the arcs is gradually fused, and the number of the arcs and the length of the passage containing the arcs is such that when the material reaches the dischargespout A4 it is entirely fused and is deposited into a suitable Crucible or like vessel, from whence it is drawn, and the molten material worked by any suitable mechanism, (not shown,) depending upon the purpose for which the material is designed to be used.

The furnace herein shown maybe used for smelting or fusing all kinds of material requiring an intense heat to reduce the same and is especially adaptable for reducing silica or silica compound in the process of making glass or like vitreous materials. By the use of the conveyer E' the rate of feed of the material through the furnace may be regu- IOC IIO

lated so as insure that the material shall be properly exposed to the heat of the furnace and properly fused. The angle of the troughlike depression a of the interior passage of the furnace will be disposed with a view to produce the required speed of the material through the furnace te properly fuse the same. The conveyer-shell inthe operation of the furnace will be maintained full of the granular material which is being fed to the furnace, so as to prevent the escape of the gases from the furnace therethrough and insure its passage through the superheating-chamber G.

It is obvious that many changes may be madein the structural details illustrated without departing from the spirit of the invention, and I do notl wish to be limited to such details, except as hereinafter made the subject of specific claims. For instance, the magnets may be disposed at right angles to the bottom of the passage, in which event said magnets may be located closer to the electrodes. Moreover, the shape and proportions of the furnace may be widely varied.

I claim as my inventionl. Au electric furnace provided with a passage which is inclined from the upper to the lower end thereof and provided in its bottom with a trough-like depression through which the material to be acted upon passes by gravity, electrodes extending into said passage with their inner ends located above the bottom of said .trough-like depression in a manner to form .a plurality of arcs in said passage ,and separate means associated with each pair of electrodes for defiecting or elongating the arcs into said depression toward the material as it passes successively beneath the pairs of electrodes.

2. An electric furnace provided with a passage which is inclined from the upper to the lower end thereof and provided in its bottom wall with a trough-like depression, electrodes extending into said passage above said troughlike depression in a manner to form a plurality of arcs in the passage between which the material to be fused is successively passed, a spout connected with the lower end of the passage and projecting outside of said furnace for withdrawing the molten material from the passage, and magnets, one associated with each pair of electrodes for defiecting or elongating the arcs into said depression toward the material as it passes successively through said arcs.

3. An electric furnace provided with a passage which is inclined from its upper to its lower end and provided in its bottom with a trough-like depression, electrodes extending into said passage above said trough-like depression in a manner to form a plurality of arcs, between which the material to be fused is successively passed, magnets, one associated with each pair of electrodes, for elongating said arcsinto said depression upon said material as it passes therethrough, means for feeding the material to the upper endv of said passage and means for withdrawing the molten material from the lower end thereof.

4. An electric furnace, provided with a passage, the bottom of which constitutes a continuous inclined plane and through which passage the material to be acted upon passes by gravity, a plurality of generally horizontal electrodes extending into said passage above the level of the path of the material therethrough and magnets, associated one with each pair of electrodes, for deiiecting the arcs downwardly upon the material as it passes beneath said arcs.

5. An electric furnace provided with a passage which is inclined from the upper to the lower end thereof, electrodes arranged to form a plurality of arcs in said passage through which the material to be fused is successively passed, means for deflecting or eiongating the arcs toward the material as it passes successively through the arcs and a plurality of pipes for directing a burning mixture upon said material before said material has reached said electrodes.

6. An electric furnace provided with a passage which is inclined from the upper to the lower end thereof and is provided iu its bottom wall with a trough-like depression7 electrodes extending into said passage above said trough-like depression and arranged to form a plurality of arcs through which the material successively passes, means for deliecting or elongating the arcs into said depression toward the material as said material passes successively through the arcs, and pipes located between the receiving end of the passage and said electrodes, for directing a burning mixture into said trough-like depression of the passage.

7. Thecombinationwithanelectricfurnace provided with a passage and with electrodes extending into'said passage in a manner to form an arc through which the material to be fused is passed, of means for feeding the electrodes into said passage as they are consumed comprising rotative shafts mounted in bearings supported on the furnace-walls and provided with screw-threaded sections, said electrodes being each provided on one side thereof with integral spiral elevations and grooves meshing with the screw-threads of the associated shaft.

S. The combiuationwith an electric furnace provided with a passage and with electrodes extending into said passage in a manner to form an arc through which the material to be fused is passed, of means for feeding the electrodes into said passage as they are consumed comprising rotative shafts mounted in bearings supported on said furnace-Walls and provided with screw-threaded sections, said electrodes being each provided on one side thereof with spiral elevations and grooves meshing with the screw-threads of the associated shafts, and means for raising and lowering said shafts to permit removal of the electrodes.

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9. In an electric furnace provided with a passage and with electrodes extending into the said passage in a manner to form an arc through which the material to be fused is passed, of means for feeding the electrodes into said passage as they are consumed, cornprising rotative shafts mounted in bearings supported on the furnace-walls and provided with screw-threaded sections, said electrodes being each provided on one side thereof with spiral elevations and grooves meshing with said screw-threads of the associated shaft and means for preventing rotation of said electrodes.

10. In an electric furnace provided with a passage and with electrodes extending into said passage, in a manner to form an are through which the material to be fused is passed, means for feeding the electrodes into said passage as they are consumed, comprising rotative shafts mounted in bearings supported on the furnace-walls, said shafts being provided with screw-threaded sections, and the electrodes being each provided on one side thereof with spiral grooves meshing with the screw-threads of the associated shaft, brackets on the outer walls of tbe furnace which supports said electrodes, and means for preventing the rotation of each electrode comprising longitudinally -arranged interlocking connections between said brackets and electrodes.

11. The combination with an electric furnace provided with a passage and electrodes extending into said passage in a manner to form an arc through which the material is passed, said electrodes consisting of detachably-joined sections, each being provided at one end with a dovetailed lug, and at its other end with a dovetailed groove, and the lugs and grooves of connected electrodes being arranged horizontally when assembled in the furnace.

12. An electric furnace provided with an interior passage, electrodes arranged to form within said passage an arc through which the material to be fused is passed, means for feeding the material to the upper end of said passaid conveyer, a pipe connecting said chamber with said furnace-passage for directing the gases of the furnace through said chamber to heat the material as it is conveyed to the furnace, and pipes for delivering a burning mixture into said passage between the discharge end of the conveyer and the electrodes for further heating said material before it reaches said electrodes.

14. A furnace provided with an interior passage, electrodes extending into said passage to form arcs therein through which the material is passed, means for delivering a granular material to said passage comprising a spiral conveyer, a chamber surrounding the con veyer-shell, a plurality of radial partitions extending between said conveyer-shell, and the wall ofv said chamber and dividing the chamber into a plurality of compartments, a pipe or passage leading from said furnacepassage into one of said compartments of said chamber, certain of the partitions of said chamber being provided with openings through which the chambers communicate one with the other, and one of said compartments communicating with an exhaust-passage for discharging the gases from said chamber.

In testimony that I claim the foregoing as my invention I affix my signature, in presence of two witnesses, this 10th day of May, A. D.

ALBERT A. SHADE. Witnesses:

WILLIAM L. HALL, GERTRUDE BRYCE. 

